4,547 research outputs found
Bandwidth efficient multi-station wireless streaming based on complete complementary sequences
Data streaming from multiple base stations to a client is recognized as a robust technique for multimedia streaming. However the resulting transmission in parallel over wireless channels poses serious challenges, especially multiple access interference, multipath fading, noise effects and synchronization. Spread spectrum techniques seem the obvious choice to mitigate these effects, but at the cost of increased bandwidth requirements. This paper proposes a solution that exploits complete complementary spectrum spreading and data compression techniques jointly to resolve the communication challenges whilst ensuring efficient use of spectrum and acceptable bit error rate. Our proposed spreading scheme reduces the required transmission bandwidth by exploiting correlation among information present at multiple base stations. Results obtained show 1.75 Mchip/sec (or 25%) reduction in transmission rate, with only up to 6 dB loss in frequency-selective channel compared to a straightforward solution based solely on complete complementary spectrum spreading
WG1N5315 - Response to Call for AIC evaluation methodologies and compression technologies for medical images: LAR Codec
This document presents the LAR image codec as a response to Call for AIC evaluation methodologies and compression technologies for medical images.This document describes the IETR response to the specific call for contributions of medical imaging technologies to be considered for AIC. The philosophy behind our coder is not to outperform JPEG2000 in compression; our goal is to propose an open source, royalty free, alternative image coder with integrated services. While keeping the compression performances in the same range as JPEG2000 but with lower complexity, our coder also provides services such as scalability, cryptography, data hiding, lossy to lossless compression, region of interest, free region representation and coding
Secure Layered Transmission in Multicast Systems with Wireless Information and Power Transfer
This paper considers downlink multicast transmit beamforming for secure
layered transmission systems with wireless simultaneous information and power
transfer. We study the power allocation algorithm design for minimizing the
total transmit power in the presence of passive eavesdroppers and energy
harvesting receivers. The algorithm design is formulated as a non-convex
optimization problem. Our problem formulation promotes the dual use of energy
signals in providing secure communication and facilitating efficient energy
transfer. Besides, we take into account a minimum required power for energy
harvesting at the idle receivers and heterogeneous quality of service (QoS)
requirements for the multicast video receivers. In light of the intractability
of the problem, we reformulate the considered problem by replacing a non-convex
probabilistic constraint with a convex deterministic constraint. Then, a
semidefinite programming relaxation (SDR) approach is adopted to obtain an
upper solution for the reformulated problem. Subsequently, sufficient
conditions for the global optimal solution of the reformulated problem are
revealed. Furthermore, we propose two suboptimal power allocation schemes based
on the upper bound solution. Simulation results demonstrate the excellent
performance and significant transmit power savings achieved by the proposed
schemes compared to isotropic energy signal generation.Comment: 7 pages, 3 figures, accepted for presentation at the IEEE
International Conference on Communications (ICC), Sydney, Australia, 201
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Multimedia delivery in the future internet
The term âNetworked Mediaâ implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizensâ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications âon the moveâ, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
Quality of Experience and Adaptation Techniques for Multimedia Communications
The widespread use of multimedia services on the World Wide Web and the advances
in end-user portable devices have recently increased the user demands for better quality.
Moreover, providing these services seamlessly and ubiquitously on wireless networks and
with user mobility poses hard challenges. To meet these challenges and fulfill the end-user
requirements, suitable strategies need to be adopted at both application level and network
level. At the application level rate and quality have to be adapted to time-varying bandwidth
limitations, whereas on the network side a mechanism for efficient use of the network
resources has to be implemented, to provide a better end-user Quality of Experience (QoE)
through better Quality of Service (QoS). The work in this thesis addresses these issues by
first investigating multi-stream rate adaptation techniques for Scalable Video Coding (SVC)
applications aimed at a fair provision of QoE to end-users. Rate Distortion (R-D) models
for real-time and non real-time video streaming have been proposed and a rate adaptation
technique is also developed to minimize with fairness the distortion of multiple videos
with difference complexities. To provide resiliency against errors, the effect of Unequal
Error protection (UXP) based on Reed Solomon (RS) encoding with erasure correction has
been also included in the proposed R-D modelling. Moreover, to improve the support of
QoE at the network level for multimedia applications sensitive to delays, jitters and packet
drops, a technique to prioritise different traffic flows using specific QoS classes within an
intermediate DiffServ network integrated with a WiMAX access system is investigated.
Simulations were performed to test the network under different congestion scenarios
Wireless multimedia sensor network technology: a survey
Wireless Multimedia Sensor Networks (WMSNs) is comprised of small embedded video motes capable of extracting the surrounding environmental information, locally processing it and then wirelessly transmitting it to parent node or sink. It is comprised of video sensor, digital signal processing unit and digital radio interface. In this paper we have surveyed existing WMSN hardware and communicationprotocol layer technologies for achieving or fulfilling the objectives of WMSN. We have also listed the various technical challenges posed by this technology while discussing the communication protocol layer technologies. Sensor networking capabilities are urgently required for some of our most important scientific and societal problems like understanding the international carbon budget, monitoring water resources, monitoring vehicle emissions and safeguarding public health. This is a daunting research challenge requiring distributed sensor systems operating in complex environments while providing assurance of reliable and accurate sensing
QUALITY-DRIVEN CROSS LAYER DESIGN FOR MULTIMEDIA SECURITY OVER RESOURCE CONSTRAINED WIRELESS SENSOR NETWORKS
The strong need for security guarantee, e.g., integrity and authenticity, as well as privacy and confidentiality in wireless multimedia services has driven the development of an emerging research area in low cost Wireless Multimedia Sensor Networks (WMSNs). Unfortunately, those conventional encryption and authentication techniques cannot be applied directly to WMSNs due to inborn challenges such as extremely limited energy, computing and bandwidth resources. This dissertation provides a quality-driven security design and resource allocation framework for WMSNs. The contribution of this dissertation bridges the inter-disciplinary research gap between high layer multimedia signal processing and low layer computer networking. It formulates the generic problem of quality-driven multimedia resource allocation in WMSNs and proposes a cross layer solution. The fundamental methodologies of multimedia selective encryption and stream authentication, and their application to digital image or video compression standards are presented. New multimedia selective encryption and stream authentication schemes are proposed at application layer, which significantly reduces encryption/authentication complexity. In addition, network resource allocation methodologies at low layers are extensively studied. An unequal error protection-based network resource allocation scheme is proposed to achieve the best effort media quality with integrity and energy efficiency guarantee. Performance evaluation results show that this cross layer framework achieves considerable energy-quality-security gain by jointly designing multimedia selective encryption/multimedia stream authentication and communication resource allocation
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